<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <!-- 求数组里有多少true -->
    <script>
      let arr = [true, true, false, false, true]
      let res = {}
      for (let i = 0; i < arr.length; i++) {
        let ai = arr[i]
        if (!res[ai]) {
          res[ai] = 1
        } else {
          res[ai]++
        }
      }
      console.log(res)
    </script>
  </body>
</html>
